• Ina | La Canada | Oro Valley 520.742.4148

Our Veterinary Team

Our Veterinary Team:

As a full service, 35 year old Veterinary Hospital with a staff of approximately 30 employees, our management, doctor and team members plays a crucial role in our success. Our staff takes pride ensuring that every visit to our practice is enjoyable for you and your pet.

Doctor Erin O’Donnell (Chief Medical Officer) and Gary Zimnoch (Chief Executive Officer) are the owners of Northwest Pet Clinic. Together, they have the strength and partnership to make this hospital run smoothly. From daily procedures to monthly meetings and seminars, our team keeps NWPC on the top with constant growth and progressive, preventative medicine.

Our Doctors offer our pet patients a vast array of knowledge, skills, and experience. Whether your pet’s needs are routine or specific, you can feel confident that they will be met. Our Doctors work as a team; they share their ideas and will often consult with each other on complicated cases. Please take a moment to learn more about them and their interests.

Dr. Erin O'Donnell, DVM-Chief Medical Officer/Co-Owner

Dr. Erin O’Donnell, DVM-Chief Medical Officer/Co-Owner

Dr. Erin O’Donnell is originally from Colorado and she attended Kansas State University College of Veterinary Medicine. After graduating in 2000, she moved to Mesa, AZ to complete an internship in small animal medicine and surgery.

Shortly after her internship, Dr. O’Donnell moved to Tucson and worked as a relief veterinarian for a variety of general and emergency practices. Dr. O’Donnell joined the Northwest Pet Clinic team full-time in 2005.

Today, Dr. O’Donnell along with her husband Gary, and our C.O.O. Jan own the practice. She loves all aspects of veterinary medicine but has a particular interest in behavior, feline medicine, internal medicine, and geriatrics.

Dr. O’Donnell and Gary enjoy desert living with their “blended family” of 5 dogs, 1 cat, and a variety of turtles and tortoises. She enjoys cactus gardening, driving and hiking in the Arizona desert, traveling, scuba diving, and visiting the annual Tucson Gem Show.

Dr. Jackson

Dr. Kasey Jackson, DVM

Dr. Kasey Jackson is a Tucson native who grew up just a few blocks from our clinic. While completing her undergraduate degree at the U of A, she obtained clinical experience by working as a veterinary assistant with Northwest Pet Clinic.

In 2011, Dr. Jackson graduated from Colorado State University and returned home to enhance her education by completing a small animal internship at the Veterinary Specialty Center of Tucson. During this time she developed a particular interest in neurology, critical care, and behavior.

Dr. Jackson is married to her high school sweetheart Colt, a paramedic/firefighter for the Northwest Fire District. Together they enjoy spending time with their three dogs (Jane, Kate, and Cody), cat (Tom) and horses (Rose and Nala).

When she’s not working you will find Dr. Jackson either horseback riding, camping, or at the lake.

Dr. Swenson

Dr. Elsa Swenson, DVM

Dr. Elsa Swenson is a 2007 graduate from Iowa State University College of Veterinary Medicine. She completed her undergraduate degree at the University of Minnesota in Animal Science and International Agriculture in 2003. She was born in Minnesota but grew up in Pittsburgh, PA. She has studied abroad extensively and had an opportunity to take veterinary courses on Wildlife Medicine and Conservation in South Africa and Veterinary Acupuncture in China as well as volunteering with Heifer International.

Following graduation from veterinary school, she completed an internship at a veterinary hospital in Tucson, then as an emergency veterinarian for a few years before switching to general practice. She did a 3 month volunteer veterinary mission with World Vets at the end of 2010 in Central and South America while living aboard the USS Iwo Jima. She has interests in soft tissue surgery, exotic pet medicine (especially rabbits!), emergency medicine and veterinary disaster response medicine. She is a Veterinary Medical Officer with National Veterinary Response Team (NVRT) which is part of the US Dept of Health and Human Services response team to natural and man-made disasters such as hurricanes, floods, wildfires, etc.

When she is not working, she enjoys spending time with her furry family, currently a dog, two cats and two chinchillas as well as traveling, hiking, and volunteering around town. On the weekends you will likely find her playing soccer in a Tucson recreation league.


Dr. AshDr. Lesley Ash, DVM

Dr. Lesley Ash is a Tucson native and received her undergraduate degree at the University of Arizona. She then moved cross-country to attend veterinary school at Tufts University in Massachusetts.

After graduating in 2014, Dr. Ash spent a year at a mixed animal practice in rural North Dakota.  There, she enjoyed working with a variety of animal species, from leopard geckos to American bison, and all sizes in between.  Her primary interests are soft tissue surgery and internal medicine.

Dr. Ash is excited to be back in warm and sunny Tucson.  When she is not working, she is continuously entertained by her two sassy felines (Layla and Orion). She also enjoys rock climbing, photography, and exploring the Arizona scenic outdoors.

dr christensenDr. Christensen was raised in Roswell, NM. She attended and graduated from the University of New Mexico with a Bachelors degree in mechanical engineering. After graduating she worked in the oil industry for 5 years. During that time, she met her husband and realized she should pursue her lifelong dream of becoming a veterinarian. In 2002, she graduated from Iowa State College of Veterinary Medicine and she and her husband moved to Tucson,AZ.

When not practicing Veterinary Medicine, she enjoys spending time with her husband, daughter, two cats, a dog, and their horses on their five acres. She also enjoys relaxing with a good book.


Our Management Team is responsible for the day to day operations for the clinical and administrative departments.

Gary Zimnoch – Chief Executive Officer/Co-Owner

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Gary Zimnoch has received decorations and citations for serving in the United States Marine Corps and served in Operation “Restore Hope” in Mogadishu, Somalia. After receiving an honorable discharge from the Marine Corps, he continued his education and studied Medical Technology.

Before Gary embarked on his Veterinary career, he worked for a National Distributor as a Merchandising Manager in Retail Space Management. As the Chief Executive Officer, Gary is very active in the Southern Arizona Veterinary Managers Group. He is also Co-Founder/COO of the United Purchasing Alliance, a buying group that provides substantial savings to Veterinary practices in Arizona.

Gary understands that he is in a service industry and values the relationship between his business and the community. Feeling an obligation to the community, Gary and Northwest Pet Clinic have sponsored “The Healthiest Town in America” event in 2010 and spring 2011. He also sits on the Board of Directors, providing information and demonstrations to local residents on preventive medicine for companion animals. Gary is a member of his local Chamber of Commerce and is also a member of Vistage.

Gary’s largest contribution to the practice has been his focus on customer service. Knowing the key to service is a great team sending a consistent message, Gary has improved employee benefits by providing a corporate gym membership and additional disability benefits for the benefits package. His team takes pride in their work and truly sees the value in all services.

Patrick Darnell - ControllerPatrick Darnell – Controller

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Patrick Darnell is a native Tucsonan and a University of Arizona graduate. He holds a bachelor’s degree in Business Administration with majors in Finance and Economics and a master’s degree in Accounting. Pat has owned and operated businesses since 1990 from Tokyo to Tucson and is enrolled to practice before the I.R.S.

He and his wife of 28 years (Amphitheater high school sweethearts) reside between both office locations with their two lovely daughters, so Pat often rides his bike to work.

Pat is an avid outdoor enthusiast and spends a lot of time hiking in the Tucson and Catalina mountain ranges. He often concludes his Sunday jaunts with a cup of coffee at the Arizona-Sonora Desert Museum.

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Karen Tegner, CVT – Operations and Facilities Manager

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Karen was born in Buffalo, NY and raised in Georgia. She transferred to Arizona via NY, CA, and VA (DC area) in August 2001. Karen absolutely loves Arizona and has adapted to life in the desert. She loves to garden and thinks cacti are just wonderful.

Always having a passion for the veterinary field, Karen found that the opportunity arrived when she moved to Arizona. After graduating with her CVT in 2004, Karen joined the staff at Northwest Pet Clinic where she had completed her externship.

Her previous career in Finance had proved a valuable skill set in her current position of as our Operations and Facilities Manager.   Karen works behind the scenes to ensure every visit to any one of our three locations is a smooth and pleasant one.

Karen has 4 of her own “kids”. Harry (a Pitbull), Saga (a Labrador), Elsie (a black/white kitty), and Simply Red (an orange tabby). When not spending her time playing with her “kids”, Karen loves to explore the beautiful outdoors of Arizona.

Amber Rayl - Hospital Manager of Ina

Amber Houston – Hospital Manager

Amber Houston began her career at Northwest Pet Clinic in August of 2005.  She began her journey as a Customer Service Representative (CSR) and quickly cross trained to the nursing side of the practice. Amber’s ability to lead her team effectively gave her the opportunity to become a Hospital Manager. She has been managing Northwest Pet Clinic since 2012.As Hospital manager, Amber oversees the daily clinical operations of the General Practice, Surgery, ICU, Emergency and Urgent Care Departments. She is excited to continue to lead nurses by example while teaching and providing other technicians with great learning opportunities.

Amber’s family consists of a mixed flock of chickens and turkeys, dogs, cats, turtles and a tortoise. In her free time, she enjoys the many hiking trails Southern Arizona has to offer, as well as tending to her homestead in Marana, AZ.

Jake Bio PicJake Huyett-Hospital Manager

Jake began his career in veterinary medicine in large animal medicine working for a Veterinarian caring for Camelids (Alpacas and Llamas) and Ovine (Sheep) in Bend Oregon, where he grew up after moving from Anchorage, Alaska.

In 2007, Jake advanced his veterinary career into primary care by moving to Tucson, Arizona.  In 2010, Jake once again advanced his career into another area of veterinary medicine; Emergency and Critical Care. Due to Jake’s ability to effectively lead clinical nursing staff, he was quickly promoted to ER/CCU Team Leader in 2013 and to an ER/CCU Manager just six months later!

In late spring of 2015, Jake joined the growing team at NWPC as a Hospital manager. Jake is very excited to be at NWPC because he gets to combine his love of primary care, emergency care, urgent care, equine care, and critical care each and every day. He enjoys the personal connection between the patients and their owners; giving him the opportunity to be more involved in other special interests such as anesthesia, feline, avian and small animal medicine.

Jake enjoys his time with his partner and their large family of critters that include his beloved Bengal cats, dogs, cockatoos, fish and a few chickens.  In his free time, Jake competitively shows his Netherland Dwarf Rabbits across the west coast and Arizona.


Sarah Pierson-Hospital Manager
Sarah began her career in 2004 as a Client Service Representative for a small, corporately owned primary care practice in Tucson, AZ. Less than a year later she was given the opportunity to become a Veterinary Technician at the same primary care practice under the direct supervision of clinic’s Chief of Staff Veterinarian. In 2006, Sarah was promoted to Hospital Manager and Lead technician.Over the next 10 years, Sarah managed the daily operations of the hospital while overseeing a support staff of twenty-five and five Veterinarians. Sarah was so successful at her job that she was elected to become a member of the corporation’s veterinary management leadership group! Her leadership duties included traveling to many other hospitals across Arizona to assist in the training and development of new veterinary team members.In September 2015, Sarah joined the Management Team at NWPC as our Service Excellence Manager. Her new role allows her to focus on her passion, client and staff education in the areas of preventive care and enhancing the client/patient hospital experience. Sarah continues to further her education pursuing a degree in nutrition at the University of Arizona. She loves the warm Tucson weather and if she is not at the gym, she spends most of her time outdoors hiking and swimming with her family and her two fur babies; a 14-year-old pitbull, and a 2-year-old pitbull/mastiff adopted from Pima Paws for Life.

The Team at Northwest Pet Clinic – Dedicated to your pet’s healthy lifestyle.


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